Android开发基础知识回顾

1.获取版本信息

public static String getVersionName(Context context) {
String versionName;
// 获取包管理器
PackageManager packageManager = context.getPackageManager();
try {
    PackageInfo packageInfo = packageManager.getPackageInfo(context.getPackageName(), 0);

    versionName = packageInfo.versionName;
} catch (NameNotFoundException e) {
    versionName = "获取版本信息错误";
    e.printStackTrace();
}
return versionName;
}

2.获取服务器版本信息

class GetServerVisionRunnable implements Runnable {
        @Override
        public void run() {
            InputStream is = null;
            BufferedReader br = null;
            try {
                // 创建连接
                HttpURLConnection connection = (HttpURLConnection) new URL(
                        "http://192.168.129.102:8080/version.json").openConnection();
                // 设置连接超时时间
                connection.setConnectTimeout(5000);
                // 设置读取超时时间
                connection.setReadTimeout(5000);
                // 连接
                connection.connect();
                String result = "";
                if (connection.getResponseCode() == 200) {

                    is = connection.getInputStream();
                    br = new BufferedReader(new InputStreamReader(is));
                    String readlline;
                    while ((readlline = br.readLine()) != null) {
                        result += readlline;
                    }
                    JSONObject json = new JSONObject(result);
                    int serverVersionCode = json.optInt("versioncode");
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                CommonUtils.CloseStream(is);
                CommonUtils.CloseStream(br);
            }
        }
    }

3.下载、安装apk

class DownloadRunnable implements Runnable {
    private InputStream inputStream;
    private FileOutputStream fos;
    private ProgressDialog pd;

    public DownloadRunnable(ProgressDialog pd) {
        this.pd = pd;
    }

    @Override
    public void run() {
        try {
            // 初始化
            HttpURLConnection connection =
                    (HttpURLConnection) new URL(downUrl).openConnection();
            connection.setConnectTimeout(5000);
            connection.setReadTimeout(5000);
            connection.connect();
            // 连接成功
            if (connection.getResponseCode() == 200) {
                // 创建文件
                File file = new File(Environment.getExternalStorageDirectory(), "test.apk");
                inputStream = connection.getInputStream();
                // 获取文件总长度
                int totalLength = connection.getContentLength();
                // 设置进度条的总大小
                pd.setMax(totalLength);
                fos = new FileOutputStream(file);
                int len;
                byte[] buffer = new byte[1024];
                int current = 0;
                while ((len = inputStream.read(buffer)) != -1) {
                    fos.write(buffer, 0, len);
                    current += len;
                    // 设置进度条的进度
                    pd.setProgress(current);
                }
                // 隐藏进度条
                pd.dismiss();
                // 安装应用
                Intent intent = new Intent();
                intent.setAction("android.intent.action.VIEW");
                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                intent.addCategory("android.intent.category.DEFAULT");              
                intent.setDataAndType(Uri.parse("file:" + file.getAbsolutePath()),
                        "application/vnd.android.package-archive");
                startActivityForResult(intent, REQ_CODE_INSTALL_APP);

            }

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            CommonUtils.CloseStream(inputStream);
            CommonUtils.CloseStream(fos);
        }
    }
}

4.动画

        //沿Y轴旋转的属性动画
        ObjectAnimator animator = ObjectAnimator.ofFloat(iv_icon, "rotationY", 0, 45, 90, 135, 180, 225, 270, 315, 360);
        // 时常
        animator.setDuration(2000);
        // 重复次数
        animator.setRepeatCount(ObjectAnimator.INFINITE);
        // 重复模式
        animator.setRepeatMode(ObjectAnimator.REVERSE);
        animator.start();

5.按钮按压效果选择器

• 在res/drawable/目录下新建一个正常状态下的shape